Apparatus and method of remote sensing

Abstract

A system for the detection of a rate of flow or a level of a fluid or the presence of an object, such as a PIG, in pipelines, comprising at least one detection device that includes: a sensor assembly arranged to detect the rate of flow or level of a fluid withing a section of a pipeline or the presence of a pig located along the section of pipeline where the device is located, a power store, a position determining module, a radio frequency receiver, and a radio frequency transmitter, in which the detection device has a sleep mode in which the sensor assembly is inactive and has a first power consumption and an active mode in which the sensor assembly is active and the detection device has a second, higher, power consumption when the sensor assembly of the device is actively detecting, the device in the active mode also being arranged to transmit signals from the transmitter that are indicative of the detected property of the fluid or presence of an apparatus along the section of the pipeline; and in which the device is configured to switch between the sleep mode and the active mode in response to radio frequency signals received by the receiver.

1 . A system for the detection of a rate of flow or a level of a fluid or the presence of an object, such as a PIG, in pipelines, comprising at least one detection device that includes:
 a sensor assembly arranged to detect the rate of flow or level of a fluid withing a section of a pipeline or the presence of a pig located along the section of pipeline where the device is located,   a power store,   a position determining module,   a radio frequency receiver, and   a radio frequency transmitter,   in which the detection device has a sleep mode in which the sensor assembly is inactive and has a first power consumption and an active mode in which the sensor assembly is active and the detection device has a second, higher, power consumption when the sensor assembly of the device is actively detecting,   the device in the active mode also being arranged to transmit signals from the transmitter that are indicative of the detected property of the fluid or presence of an apparatus along the section of the pipeline;   and in which the device is configured to switch between the sleep mode and the active mode in response to radio frequency signals received by the receiver.   
     
     
         2 . A system according to  claim 1  in which during sleep mode the sensor assembly is completely unpowered due to deactivation of the power store supplying power to the sensor assembly or isolating the sensor assembly from the power store. 
     
     
         3 . A system according to  claim 1  whereby in addition to putting the sensor assembly into an inactive state during sleep mode the device is configured to place the transmitter also into an inactive state during sleep mode so that it is not transmitting. 
     
     
         4 . A system according to  claim 1  in which the detection device is configured to respond to signals received at the receiver to switch the pig detection device between the sleep mode and active mode. 
     
     
         5 . A system according to  claim 1  in which the detection device is permanently secured to a pipe or attached using a releasable and reusable fixing. 
     
     
         6 . A system according to  claim 1  in which the detection device comprises a housing which contains the sensor assembly, transmitter and receiver and a processor. 
     
     
         7 . A system according to  claim 1  in which the sensor assembly comprises a passive sensor assembly, in particular a wideband acoustic receiver which looks for the acoustic signature associated with the presence of a moving pig. 
     
     
         8 . A system according to any one of  claim 1  in which the sensor assembly comprises an active sensor assembly, in particular an ultrasonic sensor. 
     
     
         9 . A system according to  claim 1  in which the detection device configured to cause a radio signal to be transmitted following a switch to active mode. The transmission of this signal is received by the remote controller as confirmation that the device has switched into active mode. 
     
     
         10 . A system according to any  1  which comprises two or more detection devices each having the features of any of the preceding claims. 
     
     
         11 . A system according to  claim 1  further comprising a control unit located remotely from the detection device or detection devices, the control unit being configured to transmit signals to the detection devices that are detected by the receiver of the detection device and prompt the detection device to enter or exit the sleep mode or active mode. 
     
     
         12 . A system according to  claim 11  in which the central control unit comprises a computer, such as a laptop computer and a radio transceiver for communication via RF signals to the detection device or devices. 
     
     
         13 . A system according to  claim 1  in which the position information output by the position determining module indicates an absolute position based on information from a global satellite navigation system. 
     
     
         14 . A detection device in particular for detecting a PIG in a pipeline for use in the system, as defined in  claim 1 . 
     
     
         15 . A method of detecting the position of a pig or the level or flow rate of a fluid within a section of pipeline, the method including: at a detection device of a system according to the first aspect, receiving a signal from an external source at the receiver, decoding the signal to determine if the signal encodes an instruction to send the detection device into an active mode and in that event waking up the device, with a sensor assembly of the detection device detecting the passage of a pig or the level or flow of a fluid, and transmitting a signal from a transmitter of the device indicative of the position of a pig or the level or flow rate of a fluid. 
     
     
         16 . The method of  claim 15  further comprising wakening the detection device prior to sending a pig along the pipe. 
     
     
         17 . The method of  claim 15  further comprising once a pig has been detected and a signal transmitted from the transmitter encoding the detection, automatically placing the pig detection device back into a sleep mode. 
     
     
         18 . The method of  claim 15  comprising receiving signals from the pig detection device at a central control unit and analysing the signals to determine the position of a pig. 
     
     
         19 . The method of  claim 18  comprising transmitting a signal from the central control unit to the pig detection device via a satellite that instructs the detection device to enter the sleep mode or enter the active mode.